I just bought a vice block and AR wrench, then punches and Allen wrenches and basic tools. I would definitely get the torque screw driver and a torque wrench.
Like most tools, you pay for quality. The punches take a beating. So a quality set is worth the extra expense. I think I paid $50 for the my Starrett set. For installing barrels, I like the Super Reaction Rod. But there's some similar reaction rods that work for less money. Don't for forget the roll pen starter punch. It can make you life much easier.
I bought one and have used it to build several ARs. I like the looks of the reaction rod over the upper vise clamp but haven't saved enough pennies to get one yet.